In the telecommunications industry, a commonly used piece of equipment is a terminal block which includes a plastic block having a plurality of metallic terminals mounted therein. Typically, portions of the terminals depend from the plastic block and are adapted to have conductors wrapped thereabout in close-fitting relation to establish an electrical connection.
The wrapping of conductors about these terminals is generally accomplished in a factory environment by an operator who uses a wire-wrapping tool throughout a work shift. The terminal block is generally supported on one of its edges surfaces with the depending portions of the terminals which are to be wrapped facing the tool operator.
The typical wire-wrapping tool which is pneumatically operated resembles a handgun and includes a barrel and a handle. The barrel includes a rotatable wrapping bit, which includes an opening for receiving a terminal to be wrapped, while the handle includes a trigger. The tool is generally hand-held so that the trigger is depressed by the forefinger or middle finger of the holding hand to cause a fluidic circuit to be controlled to operate the bit of the tool to wrap an end portion of a conductor about the terminal over which the bit is placed.
From an ergonomic standpoint, it is best to position the terminal block with the terminals oriented horizontally so that the tool is moved horizontally inwardly and then is withdrawn in each cycle of wrapping. Unfortunately, this orientation of the terminal block is not the best insofar as being able to align the tool with a particular terminal of the mass of terminals which depend from the block.
It has been found that the problem of alignment of tool with the terminals is overcome by supporting the block in an inclined position so that the terminals are inclined upwardly as they extend from the block toward the tool operator. While this orientation of the block overcomes the problem of sighting along the terminals to align the tool, it causes biomechanical problems for the operator. For example, the holding of the wire wrap tool by the operator results in a slight ulnar deviation. In other words, the ulnar bone in the forearm of the tool operator deviates from its normal position which causes a pull and extension on muscles of the forearm. Particularly during the above-described tedious and repetitive process of connecting wires to terminals, this pull and extension may over a period of time result in undue fatigue and in product defects.
The ergonomics of hand-held tools is not new and efforts have been made to overcome the fatigue of this operation by modifying the wire wrapping tool. For example, on page 19 of Issue 30 dated April 1973 of the Western Electric Technical Digest, there is shown a hand tool which is operated by sensing means other than a mechanical trigger. When a sensing port becomes blocked such as by the positioning of a tool operator's index finger over the port, a stream of air is diverted within a fluidic circuit which causes an air motor to operate the tool.
This just-described arrangement does not completely overcome the fatigue problem encountered in terminal block wiring. The use of the middle or index finger to depress a trigger requires the application of a force to move the trigger through a distance. This same drawback is present in guns which have been modified to include a small tube which extends along the handle of the gun, for there too, the operator must move the thumb or forefinger through a distance to cover the port to control the fluidic circuit. See page 24 of the February-March 1976 issue of the WE.RTM. magazine, WE being a registered trademark of the Western Electric Company.
What is required and what is not known in the prior art is a hand tool which is especially suitable for wrapping terminals with conductors and which is ergonomically designed to avoid problems of operator fatigue.